1. Field of the Invention
The present invention relates to a hydrocarbon liquefied gas adjusting method and apparatus.
2. Description of Related Art
Conventionally, a gas flow rate adjusting apparatus in which fuel gas is taken out of a tank through opening/closing valve means having a flow rate adjusting mechanism and ignitor. The fuel gas is, for example, a hydrocarbon base and stored in a pressure tank having a predetermined volume in a liquid form. For example, this gas flow rate adjusting apparatus is used to take out fuel gas in the field of, for example, a cigarette lighter, anignitor, and a portable gas cylinder. The cigarette lighter and other these devices contain a pressure tank capable of storing a relatively small amount of petroleum gas therein in a liquid form. The flow rate of fuel gas contained in the tank is adjusted by pressing from outside a flow rate adjusting member composed of a porous elastic foamed body such as a multi-porous spongy like material which is commonly used in cigarette lighters to adjust flow rate, hereinafter referred to as moltpren. Gas is taken out through the opening/closing valve means, and spouted from, for example, a burner nozzle so as to form a flame for igniting a cigarette. The moltpren is an elastic foamed body having continuous pores and is used for adjusting the flow rate of passing gas by changing a total area of the pores when the elastic foamed body is pressed. Such a flow rate adjusting mechanism using the moltpren has been well known and widely used to adjust the length of flame of a cigarette lighter.
When gas in a tank which stores fuel gas is adjusted with the moltpren, first, the moltpren needs to be compressed to a thickness substantially by half or more in order to secure its maximum flow rate range. The moltpren is compressed in a finer adjusting range so as to obtain a desired flame length. When the moltpren is compressed into the maximum flow rate range. It is compressed so as to ensure an arbitrary flow rate. Adjustment from its maximum value to its minimum value is achieved within compressibility in a very small range of compression. Thus, because the porous elastic foamed body is compressed with a high compressibility so as to ensure the maximum flow rate range, it is used in a condition in which it is likely to deteriorate with a passage of time and therefore, elastic restoration of the moltpren is worsened with time passage so that a stabilized flow rate adjustment cannot be achieved after a long time. Next, the moltpren is secondarily compressed further within the adjusted maxi mum flow rate range so as to obtain an arbitrary f lame length. Because this secondary compression is a compression within a very small range, the moltpren compression mechanism is constituted of a rotation mechanism such as screws. A screw mechanism must be rotated within a small angle range, so that a high precision flow rate adjusting mechanism is needed and a high cost is required. Further, because the flame length is largely changed with a small rotation operation, a fine adjustment rotation operation is needed, so that there is no easy control in obtaining an arbitrary flame length.
According to other proposed inexpensive and disposable cigarette lighters, instead of the above-described flow rate adjustment with the moltpren, the flow rate of the fuel gas is set to a predetermined amount at the time of shipment from factory using a flow rate restricting member composed of fine porous film such as membrane film. Arbitrary flow rate adjustment is prohibited. The membrane film is a porous film body having a number of fine pores through which when fluid passes. The pressure of fluid is dropped and when gas is passed through fine pores, the pressure of gas is dropped so as to restrict the maximum value of the flow rate. Although such a flow rate restricting member is capable of limiting the flow rate within a predetermined maximum value range, the fine pores in the film are kept in a predetermined size so that the sectional area cannot be changed. Therefore, the flow rate cannot be changed from outside. If gas pressure is changed due to changes in outside temperature, the flow rate is changed thereby leading to changes in flame length. A gas flow rate adjusting apparatus using such a membrane film has been disclosed in, for example, Japanese Patent Application Laid-Open No. 1993-180359.